4 tanks, I use more air than my wife so I have Super 80's and she has
2 aluminum 72's. Get aluminum tanks, they are so much lighter
aboard. Tanks are strapped into foam racks in the aft lazarette
about 1 foot from the stern platform. Our sailboat has a reverse
transom, something we felt was necessary for our diving.

Tank boots, thick neoprene boots that protect the topsides and deck.

Hose kink protectors at the high-pressure fitting. I prefer European
tank fittings to American but this isn't a big deal.

When you buy ask the dive shop to show you how to do basic
maintenance on the regulator. We both have two regulators on our
octopus for a back-up.

I carry a 2 cu ft. Spare Air. A tiny tank and regulator that is
great for just jumping overboard for a minute or two.

We both have thin skins and shorties. Even in the Caribbean a long
dive can get chilly.

We have a lobster stick for catching them and a net bag with float to
keep them away from us. Not a good idea to trail your catch close
by - sharks etc.

Both booted and non-booted fins allow us to pull on a pair quickly to
dive on the anchor.

Dive Compressor is an electric Bauer II Yachtsman. I am told by a
professional compressor service person Bauer is the best there is.
Made in Germany but sold worldwide. This is all stainless steel
compressor, 3 stage, and fills an 80 cu. ft. tank in 20 minutes from
empty. We do not have a cascade. Electric drive, 110V powered by
our genset. The fill hose runs aft to the lazarette so the tanks
can be filled in their racks. I have a set of spare valves, belts
etc. for the compressor but have never needed them. I also carry
several cartridges which are good for about 200 fills depending on
the air supply. Ours is very, very clean.

Extra snorkels. Somehow they seem to disappear.

Mask with a little magnifier glued onto the lens for looking at teeny
tiny stuff when down. Also works well in a driving rain or storm.

We have had lots of problems with aluminum tanks cracking at the neck and
corroding internally. Steel tanks seem to give heavy users fewer problems.
It is a tough call, but there are lots of really old steel tanks around and
I have thrown away quite a number of aluminum ones.

1) aluminium bottles: Here in Belgium (and I'm afraid in the rest of Europe)
very difficult to obtain and to get approved, due to regulations I think.
...
Weight is not really an argument, for the lighter your bottles, the more
lead you have to take with you. The total weight remains the same, on board
as well as while diving. And positive buoyant bottles are an annoyance when
you do decompression dives ...

2) Tank boots are to let the tanks stand upright. This should be avoided at
any moment, especially on a boat, and so it is better to leave them off.
You'll have less problems with un-noticed rust forming as well. And it only
is an annoyance when refilling, when sometimes the leads are too short to
fill bottles lying down. But this is an issue for diving centres, who teach
you to never let stand bottles, but force you to do so when refilling ...

3) ladders, getting back on board: my trick: prepare your
gear (jacket attached to bottle, regulators fitted and bottle open), blow up
your jacket, tie the lot to a rope ATTACHED TO THE BOAT ;-) , throw
everything overboard, jump overboard only dressed in suit, basic gear and
lead belt, put your gear on in the water, detach the rope (even this I've
seen people forget it, funny !) and dive. When surfacing: follow reverse
order. A point of discussion is whether to leave on your weight belt while
stepping on board, or to take it off. I prefer the latter.
Note: this method is not "general practice" on well-equipped diving boats, but
is for me the best solution when you're only two divers diving from a boat
which is not primarily meant as a diving platform. Doing it this way lets
you dive from any boat that has a (even simple) means to get back on board.
On my boat I don't even need a ladder ...

Jan, I purchased 2 of my aluminum tanks in Munich, Germany last
spring. They are approved.

Although you may certainly share a different view I prefer the alloy
bottles due to weight aboard and when above water. Handling the
extra kilos of steel on deck is always a problem on a heaving deck.
Of course when in the water who cares whether it is steel, aluminum
or whatever.

On the extra weight or lead in the water, I dive with only 2 lbs ~ 1
kilo and my wife requires about 4 lbs ~ 2 kilos. This is in the
Caribbean with warm water and little buoyancy from thick wet suits.
I would agree with you if we were wearing thick suits. We find most
people are wearing way too much weight usually brought on by their
prior experiences in cold, cold water with thick, thick suits. I
have seen 18 lbs with no suit. People have to pump up their BC to
near max just to gain equilibrium. IMHO the argument to use steel
over aluminum to put you on the bottom doesn't weight in.

I think most sailors do as we did, you carry a couple tanks and your gear
but for the most part you free-dive. It is simpler and most of the good
stuff is within twenty feet. Saving SCUBA for chores and the few times you
are some place where the diving is worth the effort and cost.

Compressors are expensive, don't like the corrosive live-aboard environment
much better than most mechanical expensive equipment. So that rare time you
do use it, it refuses to work.

So I would never suggest adding a compressor to a boat unless you are going
diving constantly.

We carried two full tanks and I think fifty percent of our use was using the
compressed air for other reasons. I had all kind of gadgets on the boat, air
nozzles, paint sprayer and such.

From Lew Hodgett on the IRBS live-aboard mailing list:

If you want pneumatic tools on board, then why not also have the correct
equipment to support them such as a small, say 5-10 gallon, ASME
certified vessel along with an engine-driven air compressor such as those
used by every 18 wheeler operating on the highway? ...

If you dive, you have to have one. As far as I'm concerned, not an optional
piece of equipment. ...

...

Forget running it off your inverter, not a chance, it'll barely run off a 5
kw generator. If you don't have a generator, you have to either get a gas or
diesel compressor, or run it off your engine (either direct drive or
hydraulics, both expensive). ...

...

I have a Bauer U10, pretty much the same compressor as the Junior. Only
difference is the frame, the pump is the same. I installed a 110 volt, 2 HP
motor and run it off a 5 KW generator. I get between 2 and 3 cu ft a minute
with the electric motor. When I need faster fills, I take it up on deck and
use the gas engine that it came with, the U10 needs no tools to change
motors, takes about 30 seconds. Absolutely no way you'll run one off an
inverter. Never get it started, forget about it.

I contacted Bauer via email and asked about the power needs of their
portable Bauer Junior system. His reply was that a minimum 8 kw genset was
required to start and run the system. He said it pulls 90 amps at startup
and 17 amps running.

> I am about to buy a 40-foot or so sailboat to live on.
> If possible, I'd like to run a SCUBA compressor with a belt-driven
> power take-off from the boat's main diesel engine.
> Is this possible, is it easy to install, what compressor could I buy,
> what RPM would that compressor need to be run at, and approximately
> how much would it cost ? I'd be doing recreational diving, so I'd
> probably be filling 4 tanks a week most of the time, maybe 12 tanks a week
> when I have guests.
>
> I'd really like to avoid adding another engine to the boat, so I don't
> want to buy a self-contained portable unit if possible.

We get this request quite often. It is not the easiest feat to accomplish.

First, Bauer will not sell a compressor block only. They only sell the
packages with the compressor, motor and filtration. Plus, when you drive a
compressor directly from your diesel, this voids the warranty.

Second, you need to take into account how you will engage/disengage the
compressor, drain the condensate drains, change the oil/filters, and run the
compressor at a constant rpm.

Third, the compression of air from ambient to 5000 psi creates heat, thus
the compressor needs adequate cooling. Being next to your diesel engine is
not the best place for cooling.

I am by no means saying that this cannot be done. But, taking everything
into account, it is difficult.

> Is Bauer the only game in town ?
> Does anyone else sell a "compressor block" ?

No, Bauer is not the only game. There is Max-Air. I just spoke to Andre
with Max-Air and they do not sell the block only either.

> If you get this request a lot, maybe it would be lucrative for you to
> design a solution ?

There is no universal "solution". Every boat is different and there are
problems that are intrinsic to the goal.

> I don't know how the "constant RPM" requirement could be solved.
> How strict is that requirement ?

Fairly strict. It is not reccommended to run above or below the guidelines
of RPM for proper lubrication of the compressor.

How could one connect a SCUBA compressor (for filling SCUBA tanks) to a power-takeoff from the
main engine of the boat ?

I think you'd need:
1- fan belt from engine to compressor
2- some kind of belt/pulley clutch so the compressor runs only when you want it to
3- keep engine at specific RPM so compressor runs at proper RPM
4- some way to cool the compressor
5- somewhere to buy the compressor and any controls/gauges
6- maybe a water-trough to cool the SCUBA tank being filled

Has anyone done this ? I assume there are easy solutions to #2, but how did you solve #4 and #5 ?

and got these responses:
From Jay Jones:

... Depending on
compressor size it could take some time to fill a tank (my 4cfm takes
over an hour). ...

I've been on lots of dive boats of all sizes 15' to 300' never seen
a p.t.o. compressor but don't see any reason it couldn't be rigged.

We have owned two scuba compressors and used each for 1 year
aboard two different boats in Mexico
and French Polynesia. The first was a gasoline-powered
compressor (5 hp Honda engine) bolted on the
deck of a 42' steel sailboat. The second, which we currently
still own, is an electric-powered
Braun Jr, mounted below-deck on a 53' sailboat.

Both compressors have given good service but we greatly
prefer the electric compressor. If you
have a genset, this is the way to go. You definitely
do NOT want to go direct-drive off of the
engine. I was advised against this 6 years ago by a
dive-boat operator and observed first-hand the
result of this type of installation on another boat.

Dive compressors put out a lot of heat and need a
very large amount of ventilation to prevent
overheating. Sticking them in a confined space with
a hot engine is a recipe for failure. The
other boat I mentioned had a genset with direct-drive
of the scuba compressor mounted in a
small space under the chart table. The compressor
literally blew up with flying shrapnel
etc. Upon post-mortem it was obvious that the failure was due to overheating.

If you don't have the space then I would advise
the above-deck gasoline engine powered compressor.
We had friends with a Tartan 34 who did a very large
amount of diving on a year trip through
Mexico and French Polynesia with a gasoline compressor
they kept in their cockpit.

If you go the below-decks route, you need to make
provisions for draining the condensate. Since its
oily and yucky you don't want it draining into the bilge.
Standard practice above-decks is to just
(somewhat unecologically) blow it into the air.
Below decks you need to collect it in some kind of
container with an air/oil separator. You have to do
this every 15 minutes or so while filling a
tank. There are automatic ways to do this but they
add some complexity. We have such an automatic
arrangement and I can provide info if desired.

...

The deck-mounted compressor was on our steel boat
which featured a raised "poop" deck at the
stern. It was a semi-custom mating of a 5 Hp Honda
to a Stewart Warner compressor fabricated by a
guy associated with a local dive shop. This was in 1995
so I have no idea whether they make them
any more.

We used rubber/metal engine mounts to bolt the compressor
frame to the deck more or less
permanently. Then we had an aluminum box fabricated that
was secured to the compressor frame by 4
"quick pins". This made a nice seat underway since the
compressor was right next to an existing
deck box. Bolting things like this is one of the nice
things about a steel boat. The box wasn't
watertight on the bottom but did keep even serious
spray off the compressor. And the poop deck
was high enough that you never got a boarding wave.
We sprayed the compressor with Boeshield
periodically and didn't have any serious corrosion problems.

As far as the automatic condensate drain ... Bauer makes
a timer/drain unit for their larger 4-stage
compressors that the installer of our (3-stage Bauer Jr)
incorrectly adapted. It initially sort
of worked. However, after we had accumulated about
100 hours of usage, the time to fill a tank
became almost double what it should have been (from
about 25 mins to 50 mins). It turned out that
this was due to the drain valves leaking.
They are pneumatically-actuated by an electric timer.
The actuation air is intended to be a few hundred PSI and
is taken from the 2nd stage on Bauer's 4-stage
compressor. However, on the 3-stage Bauer Jr, the
1st stage has only 100 PSI and the 2nd
stage has many hundreds of PSI. This is either
too little or too much. The installer chose too
little and the result was too little pressure to
hold the valves closed.

To make a long story short we had the Bauer rep in
Hawaii, "Pressure Systems Inc", fabricate a
custom mod to this setup that involved some parts
from an aircraft landing gear control that made
it work correctly given the pressures available.
The bottom line is that I'm not sure that there
is a stock setup available to meet your needs. However,
it really is true that the intermediate
and final stages need to be drained that often on the
Bauer. On our earlier compressor you could
get away with one tank fill (about 25 mins).
The old compressor was cleverly arranged so that the act
of disconnecting the tank also caused the draining
so that you couldn't mess up. On the Bauer, if
you don't do the draining there is no backup and
bad things will happen.

From Paul Cayley:

One should be fairly careful with any air supply - many "oiless" compressors
are teflon lined - and are not filtered and thus unsafe as a breathing air
source. ...

From SSSA article by Robert Rossier in Sept/Oct 1997 issue of "Alert Diver" magazine:

Hoses are slightly buoyant, to avoid entanglement.
Good to use food-grade hoses with opaque sheathing to avoid growth on insides.

Very important: avoid engine exhaust entering air intake.

Air comes out of compressor at high temperature, so must be cooled.
Also, compressor gets very hot, so handle carefully after using it.

Air is supplied at different/lower pressure than normal SCUBA setup, so
a special regulator is required.

Since both/all divers are using same air supply, no point to each diver having
an "octopus" for sharing tank. But if compressor quits, all divers will have no
air very suddenly. Must carry emergency supplies (pony bottles).

Some advantages of SSSA: fuel tank may give up to 3-hour air supply, more
than a SCUBA tank; buddies are tethered to compressor, so they can't get separated;
less equipment to store and haul; easier to enter/exit the water.

A friend owns an Airline hookah rig I use regularly.
It's nice but my complaint is it's quite a
heavy and awkward piece of equipment to tote around.
I like it when the diving will be an all-day
event but it's a bit much to mess with for just a
quick trip over the side. Without fail, it must
be rinsed after EVERY use in salt water. Other than
that it requires the normal amount of
maintenance (oil changes, etc) as any other engine.
The rest is pretty much keeping everything
clean and corrosion-free. In all but storm conditions
it simply won't get flooded with water,
capsize, sink or any other bad stuff. It's pretty robust
and very reliable. My complaint is the
bulky clumsiness (and the engine noise for those remaining topside).

I have no direct experience with the Brownie Third Lung but,
just looking at them, they seem
pretty similar. A Honda engine is the biggest part, they are
much more durable than a Briggs and
Stratton and they both use them. It's hard to say if there
is a meaningful difference in the
compressors. To my eye the Airline looks a bit more robust,
but Brownies are more common so parts
may be easier to find.

If they are already SCUBA divers, there's another possibility:
for a quick trip over the side I have
a Brownie Yacht Tender, really just a long hose (60', though
I'd recommend the longest hose you
can get) that hooks to a regular SCUBA tank.
For scrubbing the bottom, checking the prop or
un-sticking an anchor it's great. The tank stays
in the storage rack below and the hose just leads
outside. It sets up in about 2 minutes. I use it diving
sometimes too, though a day of diving
makes it more worth donning all the scuba gear. There's
really no maintenance and if needed it can
be put away without rinsing until it's convienient.
I do, of course, have to mess with getting
tanks refilled but, for me, that's something I'd be
doing anyway. If you don't dive or aren't near
a refilling station, choosing the the compressor type
may be more reasonable. The cost is an issue,
too. The gasoline-powered ones are, what, $2500 at least.
A Yacht Tender is about $250 on eBay and
the difference would buy a lot of air tanks.

I see the choice as what you want the hassle to be:
lugging around SCUBA tanks to be refilled or
lugging around a pretty hefty hunk of machinery when diving.
I SCUBA dive anyway so the Yacht
Tender is my choice.

For diving on the boat to do work and maintenance, however,
we use a homemade hooka built from a
12V truck tire inflator (relatively high pressure,
rather low volume), a collecting tank, and hose
and regulators.

...

We bought the truck tire pump in Australia from
Bumpa to Bumpa (?) - didn't cost much, maybe about
$15-$25 US. The bottles Peter found in Indonesia - he
originally wanted to use a new propane bottle
to accumulate the air, but that was expensive, and these
bottles were rated for a higher pressure
than we needed. We found these in one of those
everything-stores (a little food, a little
hardware, a couple t-shirts, etc), had no idea what
they were for, but they looked as if they'd
do the job, so Peter bought them. I think that the
Vetus pressure accumulator thingy (for your
pressure fresh-water system) would work, but that
was horribly expensive compared to these bottles
- they're quite small, the reason there are two of them.

The hoses (40') and regulators are standard SCUBA gear - you
do not want air forced into your lungs.

Because the tire inflator is high pressure but low volume,
this is okay for cleaning the bottom of
your boat, but if you exert yourself too much you're going
to breathe faster than this little pump
can produce. On the other hand, it's really sturdy,
already has a cigarette lighter plug, and
ours, built in 1996/7 hasn't missed a beat yet.

I might add that the reason that Peter built this was
because I got sick of using our dinghy air
pump to pump air to him while he cleaned the bottom of
the boat - it was easier (for him) than
setting up the hookah or any other option. Also: Peter's
had to dive on our rudder and prop in the
middle of the ocean several times to free our prop from
chunks of fish nets or other line, and
having this setup, which is ready to go in five minutes,
makes it quick and leaves me free to keep
watch in case anything went wrong (nothing did, Phew!).

You know, for about the same price
as a brand-new hookah setup you could get a compressor
to refill scuba tanks. An ultra-hardcore
diving friend has one on his boat and they work well,
though they introduce their own hassles, too.

We use ours for bottom cleaning mostly.
It's a home-assembled rig with an electric 2 HP oilless
compressor and tank, a 'T' into two 100'
hoses and two hookah regulators (also can be used for just
one if desired). Total cost: about
$390. We run it from shorepower while dockside, or generator
or inverter when away from the dock.

I have a little experience with diving. (Navy salvage diver,
though that was -ahem- a few years
ago.) I'd consider the surface-supplied air as
a good alternative for the casual diver, provided
you get basic instruction in diving. You don't need
to be certified as a diver for the smaller
floating units, most of which I believe go only to 30-40 feet,
about 1 atmosphere. You can't get
in a lot of trouble at that depth [unless you hold your breath while
ascending, or panic, or ...]. Not requiring certification
is a plus for the occasional dive
over the side for fun or to do some hull work.
It's fun at that depth; the light is usually not
that great when you're much deeper anyway.
(Depends on where you are, of course.)

I think one of these systems would have been great
to have during the 6 months of cruising I did
recently. Here's the thing as I see it: if I'm over
the side with tanks (or surface-supplied air)
and I get a little tangled up, it's a minor annoyance.
If I'm snorkeling and holding my breath and
get tangled, it's a Problem. I am pretty well trained,
though not as experienced as some here,
certainly not recent, and I think about that every time
I snorkel down. "Rule 1 - Do NOT get
tangled in anything ..." I had a line around my prop
once and it took two of us an hour of
up-and-down diving to clear it. With a surface-supplied system
I bet I could have done it myself
in 5 minutes.

For those taking longer hoses (someone mentioned 100')
you really need to be certified. At those
depths you need the same training and experience as any
other diver. In fact, I would not want to
go more than 40' with anything unless my quals were
up to date and I had recent experience. Just
not worth the risk.

Finally, not to appear critical of anyone's personal
preferences or skills, I would recommend
against "homemade" systems for the casual or novice user.
They just seem to be a risk not worth
taking. That is especially true for someone who might
read this post and think, "Hey, I can put
together my own dive system on a shoestring budget
and go down to 75 feet !!" Somebody doing that
needs a check-up from the neck-up.

Just my observations. Your mileage may vary.
I've been known to be wrong before.

Caring for rubber SCUBA gear: rinse with fresh water, dry it but not in direct sunlight,
store in dark place.
Wash with baking soda solution to remove odors.

Skin diving under hull:
drop a weight on a buoyed line,
and grab it to pull yourself below surface as needed.

Snorkeling or diving in a pass to a lagoon: dive during incoming tide,
or slack before incoming tide, for safety and best visibility.

From John Dunsmoor:

Re: snorkeling under boat with extended snorkel tube to the surface:

Try it, you are going to find an amazing amount of effort to draw air as depth increases.
It all has to do with our body mechanics, and when we do not have an air pump to move air,
we expand the space our lungs take up using the diaphragm. When you put body under pressure
then we have to displace water pressure, and not zero ambient air pressure so
the difference between what the stomach and diaphragm are working against,
in comparison to the surface air pressure is amazing. Just the difference in
pressure vs. depth, compared to surface air pressure is dramatic.

[I had mentioned that exhaling into a long tube would not exhaust the bad air out of
the tube; it would tend to "oscillate" inside the tube and you breathed in and out.]
The travel for bad air is a definite problem, this has to do with tube volume.
While one would think that a large bore would be better, the fact is a small tube
diameter would allow the two liters of air to completely vent before taking in the next breath.
Plus we only use about 20% of the oxygen we take in anyway. Simple solution would be,
do not exhaust air out the tube, exhaust the air into the water. If you want
to get more sophisticated you could have a double snorkel and valve to exhaust used air.

But you will never get to that point. You will find it very difficult to pull
air two feet down. You have to try this.

If you are focused on trying to work something out that does not require air fills,
what you need is an oil-less compressor, that has a capacity of one to two cubic feet
per minute at about 30 psi. This should provide a continuous stream of air out
the end of a tube. Kind of like the Weeki Wachee Mermaids use. Good to ten to twenty feet I would guess.

Diving in Florida:

From Gary Elder:

> Someone said "The gulf waters are shallow and
> provide little to see while diving. There are a few
> shipwrecks and man-made reefs which I have dived, but
> visibility ranges from only 2 feet to at best 10."

Twenty five miles off Marco Island the water depth is about 65'. Off Naples
that depth is a little closer to shore. Much of the Keys diving (bayside) is
in water less than 12' deep, but the visibility is much better than off
Naples. In the Keys there are lots of lobster waiting to be picked up.

There are some shipwrecks and man made reefs that are well-charted, but I
have never heard anyone complain about visibility being less than 10', even
after a storm. I think 20' is more the norm, better in the Keys.
Also, there are approx a half dozen giant towers in the gulf that are
accessible to divers ... Good fishing in 60' or so. If memory serves, the
northern most tower is at approx the Naples/ Marco latitude about 25NM
offshore. They run in a line down towards the Dry Tortugas.

Additionally, there are a couple of 'holes' nearby. One is called the Blue
Hole, the other one is called the Black Hole. I think there may be another
one, but I'm not sure. These are good places to see giant Jewfish. I'm not
sure, but it seems like they may be about 100' deep.

From John Dunsmoor:

> Someone said "The gulf waters are shallow and
> provide little to see while diving. There are a few
> shipwrecks and man-made reefs which I have dived, but
> visibility ranges from only 2 feet to at best 10."

Pretty close, ten thousand acres of flat rock bottom with a little grass.
Visibility can be better, twenty miles out you can get pretty nice.
But the water is not tropical.
No aqua-marine greens and blues like the Atlantic.

Certainly not the diving capital of the world.
But then again with the right attitude, I have been talked into
and had fun diving, in waters a whole lot less than the Gulf.

More from Gary Elder:

Talked to a dive instructor today who told me that "in the
Gulf, from early May thru Sept you can expect to see 60 - 70' visibility,
while in the Keys you can expect it to be good all year".

My experience so far (snorkeling):

All the nice coral in the Florida Keys (and much of the eastern Caribbean) has died off.
Lots of grey down there now.

The standard anchorages in the Bahamas are barren; nothing to see.
But the Exuma land and sea park has plenty of good fish to see.
And I hear the (rougher) ocean reefs are great.

The river and harbor water in the east coast ICW has zero visibility.

Avoiding jellyfish stings:

Wear nylon pantyhose over your head, under the mask, to cover exposed skin.

Coat exposed skin with baby oil or vaseline.

Why I don't SCUBA-dive:

I got YMCA-certified in California (Monterey Bay). Never bought any equipment. I snorkel instead of diving.

Most of my SCUBA instructors, including several young guys, had hearing damage.

Getting tanks refilled while cruising is difficult in some places, easy in others.
Tourist-type places have dive shops; other harbors don't. For example, along the entire
south coast of Puerto Rico, the only waterfront dive shop I'm aware of is in La Parguera.
Of course, good dive areas would tend to have dive shops nearby.

In 7+ years aboard, I haven't met anyone who refills their own tanks on their boat, but I haven't
really asked around.

As a solo cruiser, finding a buddy to dive with would be difficult most of the time.
Most cruisers snorkel. The few that dive usually do it to scrape boat hulls, for money.

The key reason: Unless I dove often and kept my skills and instincts sharp, I feel I'd be likely to kill
myself. One moment of mistake and panic at 60 feet could do it.

Snorkeling works fine for recreation and for scraping the hull. I'm sure diving would
open up a lot more areas for recreation.

About 16 years ago some island governments started requiring that all diving be done
with a local dive shop. The banning of independent diving spread.
About half of the English-speaking Eastern Caribbean islands now ban independent diving.

...

Only a limited number of really good dive spots are easily accessible by dinghy,
and for the rest it is much easier to go in a dive shop's boat. ...

Another factor in the islands: where would you have to go for treatment if you got the "bends" ?
In 10/2012 a local fishing-diver on Grenada got the bends, and it seems the nearest
hyperbaric chambers are in Barbados and St Lucia.